centos7.5固定局域网ip

有de时候，比如像我们单位，没事干就停一次网，结果ip变了，还得重新看ip，重新配置，很麻烦，所以干脆把自己ip固定，以不变应万变！！！

1.首先查看自己的ip是什么：

$ ifconfig
eno1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.16.13.196  netmask 255.255.255.0  broadcast 172.16.13.*
        inet6 fe80::f3ec:2efd:b99a:*  prefixlen 64  scopeid 0x20<link>
        ether 4c:cc:6a:*:*:*  txqueuelen 1000  (Ethernet)
        RX packets 3579688  bytes 1315908957 (1.2 GiB)
        RX errors 0  dropped 53  overruns 0  frame 0
        TX packets 959049  bytes 160239316 (152.8 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 16  memory 0xdf100000-df120000  

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 50192  bytes 17673476 (16.8 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 50192  bytes 17673476 (16.8 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

virbr0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 192.168.122.1  netmask 255.255.255.0  broadcast 192.168.122.255
        ether 52:54:00:e7:f2:e5  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

发现有三个网卡设备，其中eno1是我们的有线网卡，ip地址是172.16.13.196，netmask是255.255.255.0；

2.另一方面查看gateway和DNS是什么：

Gateway:

$ netstat -rn
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
0.0.0.0         172.16.*.*   0.0.0.0         UG        0 0          0 eno1
172.16.13.0     0.0.0.0         255.255.255.0   U         0 0          0 eno1
192.168.122.0   0.0.0.0         255.255.255.0   U         0 0          0 virbr0

gateway为172.16.*.*

DNS:

$ cat /etc/resolv.conf
# Generated by NetworkManager
nameserver 159.226.*.*

DNS为159.226.*.*

3.得到需要的信息后，更改网络配置文件：

vim /etc/sysconfig/network-scripts/ifcfg-eno1

在最后加上下面这几句话：

IPADDR=172.16.13.196
GATEWAY=172.16.13.254
NETMASK=255.255.255.0
DNS1=159.226.8.6

同时把 BOOTPROTO="dhcp" 变更为 BOOTPROTO="static" 

4.重启网络：

service network restart
Restarting network (via systemctl):                        [  OK  ]

完成！